Salt water is known for producing its own chlorine and having benefits for your skin, it is great, in a pool not a spa however. Salt water will corrode heater elements, pumps, gaskets, etc., fast in such a small body of water, it will also create a relaxing aroma of hot, chlorinated, salty water. The ozone system on the other hand eats the residual chlorine in the spa only leaving the chemical properties to sanitize but not have the feel or smell. It mimics the salt water system leaving your skin feeling soft without corroding parts of the spa.